Aircraft.



I. SCHAFRAN.

AIRCRAFT.

APPLICATION HLED MAR 18, 1918.

1 ,289,276 Patented Dec. 31, 1918.

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pvm/vrol? A TTOR/VE V vI. SCHAFRAN.

AIRCRAFT.

APPLICATION FILED MAR 18,1918.

11,289,276. Patented D60.31,1918.

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ISAAC SCHAFRAN, 0F NEWARK, NEW JERSEY, ASSIGNOR 0F ONE-HALF T0 JACOB THALER, OF NEW YORK, N. Y.

AIRCRAFT.

Specification of Letters Patent.

Patented Dec. 31, 1918.

Application filed- March 18, 1918. Serial No. 223,124.

To all whom it may concern:

Be it known that I, IsAAo SOHAFRAN, a citizen of Roumania, and resident of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Aircraft, of which the following is a specification.

This invention relates to aircraft, and my improvements are directed to means whereby the lift of the supporting unit may be increased through the direct agency of the propelling unit by rarefying the air in the region above the supporting unit, and by increasing the tension of the supporting pressures in the region below the supporting unit.

The supporting aerofoils of present day types of airplanes are set at such attacking angles of incidence and are given such contours and camber, that, as driven forwardly, the effects of suction are depended upon to rarefy the air over the upper surface of the aerofoil, and thus assist the pressure lift that occurs at the under surface of the aerofoil. Hence the lift value arising from the creation of a state of rarefaction over the aerofoil is appreciated by airplane designers, who, however, appear to have so far limited their efforts to what may be termed the inherent or natural manner of functioning, by which I mean that the design and angle of the aerofoil have been arranged to produce, at a given speed of travel, or at a sustaining air pressure, a maximum amount of entrainment or suction which results in the production of a partial vacuum over a portion of the aerofoil surface. But, apparently no effort has hitherto been made to employ mechanical means for the purpose of setting up a more powerful suction efiect which will positively evacuate the air over a major portion or the whole upper surface of the supporting aerofoil; which is the aim of my present invention for the purpose of largely diminishing the downward pressure upon the aerofoil so that the lift of the upwardly directed pressure may be more efiective.

For ractical purposes I make use of the propelling unit in an example where my invention is carried into efiect, utilizing the propeller whose thrust drives the airplane 1n its direction of travel, to continually clear the air from the region above and to compress it in the region below the aerofoil, for the purpose indicated. In this manner the tractive function of the propeller is supplemented by its further function of exhausting the downward air pressure, without increase in effort, and at the same time stiffening the resistance ofthe supporting pressures. Hence, by this means an airplane having a smaller supporting surface may be given the same lift as one having a larger area of support, with the same motor power.

Other features and advantages of my said invention will hereinafter appear.

In the drawings Figure 1 is a plan view of an airplane contalning my improvement.

Fig. 2 is a side elevation thereof.

Fig. 3 is a front view.

(Fiig. 4 is a plan view of a modification, an

Fig. 5 is a side elevation of Fig. 4.

While in the drawings I have shown my invention as applied to a monoplane type of airplane, this is merely by way of example, because the principle involved is not limited in its application to any particular type of alrplane; and, in fact, it may also be employed in conjunction with other classes of aircraft.

Mainly the invention may be considered as residing in a particular relation between an alr craft supporting aerofoil or aerofoils and its propeller or propellers for the achievement of the desired results, and, for convenience I may in the following description, refer to these elements respectively as the supporting unit and the propelling unit.

Referring first to Figs. 1, 2 and 3, the numeral 1 indicates an airplane fuselage, 2 the supporting unit. mounted on struts 3: ft the motor, and 5 the propellers mounted, in separate series, respectively, at opposite ends of the wing spread; said series of propellers being respectively carried by the shafts 6, 7, which are journaled in bearings 8, that are secured upon the supporting unit 2 by standards 9. The shafts 6, 7, are suitably driven from the engine shaft 10, as by the sprocket chains 11, 12, one of said chains being crossed, as an expedient whereby the shafts 6, 7, ma y be rotated in opposite directions.

It should be particularly noted that the shafts 6, 7, are respectively located parallel with and above the opposite outer ends of the supporting unit, near the edges thereof, so that the series of propellers, comprising the propeller unit, exert their thrust in the direction of the line of flight of the aircraft. Another feature to which attention is directed is that the propellers, which are mounted a sufiicient height above the supporting unit to clear 1ts upper surface, have a radius of rotation which is approximately one half over the supporting unit and. the other half outside the span of said unit.

The direction of rotation of the respective series of propellers is downward outwardly and upward inwardly, so that the upward strokes of the propeller blades tend to draw air upwardly away from the top surface of the supporting unit, and the downward strokes of said blades tend to press air downwardly to the region beneath the supporting unit, where, by elastic reaction, it will supplement the upward pressure forces.

In the example presented I have shown series of four propellers on each shaft, adjacent propellers in a series being arranged at right angles, to in this manner provide quartering blades for each pair, whereby the air currentsset in motion by one blade are reacted upon the quartered blade of an adjacent propeller. I aim by these means to attain the most efiicient pressure service-from the downward strokes of the propeller unit; and, in its upward strokes, to most completely evacuate the downward air pressure from the upper surface of the supporting unit. Thus, while the propelling unit is exerting its thrust-for forward motion of the aircraft, it is'at the same time coordinating the vertical pressure forces into dynamic lift with respect to both the upperv and lower surfaces of the supporting unit.

The number of propellers in a series upon the shafts 6, 7, will depend upon the extent of the wing chord and the size of the propellers, but my purpose is to employ a propeller capacity, with series of propellers placed over opposite ends of the wing span, whereby the region above the upper surface of'the supporting unit will'be most efliciently relieved, and whereby downwardly exerted pressures of air will react to the enhancement of the u ward supporting pressures.

In the modlfication shown in Figs. 4 and 5 I have indicated a supporting unit 1 3, whose aspect ratio comprises a narrow leading edge and lengthened chord, the propellers 14, in this instance being disposed in series of groups over and along the op osite side edges of said supporting unit, sai propellers functioning in the same manner as expressed for the preceding example, and thereby rendering fpracticable the employment of this novel orm of supporting unit.

Variations may be resorted to within the spirit and scope of my said invention and parts thereof used without others.

I claim 1. In an aircraft having a supporting unit and a vertical propelling unit, for horizontal propulsion, the arrangement of said propelling unit wholly above and partially over said supporting unit, with the axisof sa d propelling unit parallel to the chord of said supporting unit, whereby said propelling unit also functions to diminish the air pressure acting upon the upper surface of said supporting unit.

2. In an aircraft having a supporting unit and a vertical propelling unit, for horizontal propulsion, the arrangement of said propelling unit wholly above and partially over said supporting unit, with the axis of said propelling unit parallel to the chord of said supporting unit, whereby said propelling exhaust air from the upper surface of the supporting unit, and to compress air against the under surface thereof.

4. In an aircraft having a supporting unit, the combination of a propelling unit comprising a series of vertical propellers extending wholly above and partially over opposite sides of said supporting unit, with the axes of said propellers parallel to the chord 'of said supporting unit, adjacent propellers in a series presenting their blades in quartering relation, and said ropellers arranged to exercise power thrust or. horizontal travel of the aircraft, while also serving to diminish the vertical pressure forces in the region above, and to augment said forces in the region beneath said supporting unit.

5. In an aircraft having a supporting unit and a fixed, vertical propelling unit, for horizontal propulsion, the arrangement of said propelling unit wholly above and partially over said supporting unit, whereby said propelling unit also functions to diminish the air pressure acting upon the upper surface of said supporting unit.

6. In an aircraft having a supporting unit and a fixed, vertical propellingunit, for horizontal propulsion, the arrangement of said propelling unit wholly above and partially over said supporting unit, whereby said propelling unit further functions to both diminish the downwardly acting air to exhaust air from the upper. surface of the pressures and to increase the upwardly actsupporting unit and to compress air against ing air pressure with respect to said supthe under surface thereof.

porting unit. Signed at the borough of Manhattan,.in

5 7. In an alrcraft having a supporting unit the city, county, and State of New York, 15

and a fixed, vertical propelling unit, the this 15th day of March, A. D. 1918.

arrangement of the latter wholly above and ISAAC SCHAFRAN.- partially over the former, whereby said pro- Witnesses: I pelhng unit, While exercising power thrust F. W. BARKER,

10 for horizontal travel of the aircraft, tends A. B. BARKER. 

